(Corrects paragraph 1 to “striking a deal” from “as part of a deal” and paragraph 8 to drop “hiring of MacMillan”)

March 14 (Reuters) - Medical device maker Hologic Inc appointed a former Johnson & Johnson executive as chief operating officer, three months after naming a new chief executive and striking a deal with activist investor Carl Icahn.

Hologic, which makes screening tests for cancer and other diseases, also announced the planned retirement of Chief Financial Officer Glenn Muir, who has served in the position since 1992.

Eric Compton, who will immediately assume the newly-created COO role, also worked with consumer giant Procter & Gamble Co , and has a record of successfully turning around flagging businesses, Hologic said in a statement.

The company has been struggling with cuts in hospital spending, a lack of reimbursement for one of its mammography systems, and its troubled $3.75 billion acquisition and integration of Gen-Probe Inc.

“We believe these senior management changes are positive steps toward turning Hologic around after numerous pricey acquisitions and in light of several secular headwinds to growth,” Cowen and Co analyst Doug Schenkel wrote in a note.

With Friday’s appointments, Hologic’s entire top rank would have changed since December, when the company named former Stryker Corp CEO Stephen MacMillan as its top executive.

MacMillan’s appointment came a month after billionaire investor Ichan took a stake in the company and pushed for representation on the board in an effort to boost shareholder value.

Icahn, Hologic’s largest shareholder with a 12.5 percent stake, struck a deal with the company resulting in the appointment of two directors backed by Icahn.

Icahn was not immediately available for comment on Friday.

Hologic shares closed at $21.50 on Thursday on the Nasdaq. (Reporting by Esha Dey in Bangalore; Editing by Savio D‘Souza)